The proof is essentially a tensorization of the construction of [1]}. Fix \(k, n\in \mathbb {N}\) . Set \(L = \log _2(k+1)\)  and assume that \(L \in \mathbb {N}\)  without loss of generality. Let us consider the partial concept class
\(\mathcal {H}_n = \mathcal {H}_n^{(1)} \times \ldots \times \mathcal {H}_n^{(L)}\,,\) 
